Indoor units of air conditioners having an air filter at an air inlet have been known. In an indoor unit of this type, an air blowing fan and a drive motor are arranged substantially in the center of a casing, a heat exchanger is arranged outside the air blowing fan, a front panel having a suction grille is arranged on the front side of the casing, and an air guider is arranged between the front panel and the air blowing fan. Room air is sucked through the suction grille by the air blowing fan, and is supplied to the heat exchanger through the air guider. Then, the air that exchanged heat in the heat exchanger is blown out through outlets formed in the front panel outside the suction grille.
A measure to maintain electrical components arranged inside the indoor unit is described in, e.g., Patent Document 1. Patent Document 1 discloses an indoor unit of an air conditioner including an air filter attached to an air inlet, and a dust removing section for removing dust trapped on the air filter, wherein a claw is formed on a tray to which the air filter is attached, and is inserted in an engagement hole of a drive member. The tray is rotated downward by detaching the claw from the engagement hole, thereby allowing for maintenance of the inside of the casing.    Patent Document 1: Japanese Patent Publication No. 2005-83612